(i) Field of the Invention
This invention relates to a novel, water-soluble, metal-working lubricant composition, and more specifically to a water-soluble metal-working lubricant composition which contains one or more of specific polyetherpolyols and their derivatives and one or more compounds selected from phosphoric acid compounds and boric acid and are useful as a lubricant upon working metals, e.g., upon plastic-working, cutting and grindworking metals or for similar purposes.
(ii) Description of the Prior Art
Liquid-like oil-base lubricants which have conventionally been employed for the plastic working, cutting and grinding of metals are applied to lubricating parts as they are. Besides, they are also emulsified in water to desired concentrations by means of emulsifiers such as surfactants and are applied as emulsions to the surfaces of workpieces upon working the workpieces. Namely, such liquid-like oil-base lubricants feature that their lubricating effects can be obtained by adhesion of droplets of the liquid-like oil-base lubricants emulsified by the surfactants or the like on the surfaces of the workpieces. Liquid-like oil-base lubricants which make use of water are particularly advantageous owing to their cooling effects for heat to be produced upon working workpieces, their economy derived from recirculated use of emulsions, and so on. On the other hand, they are also accompanied by various drawbacks with respect to control of emulsions, which include:
(a) Poor stability of emulsions; PA1 (b) Inclusion of foreign matters such as metal powder, scum and the like, which occur during machining of metals, in emulsions; PA1 (c) Fouling of surfaces of workpieces due to such foreign matters; PA1 (d) Reduction to load resistant capacity due to reduced amounts of emulsified lubricant droplets adhered to surfaces of workpieces, which reduced amounts of emulsified lubricant droplets are induced to ensure stabilized emulsification; PA1 (e) Difficulty in treating waste water produced from emulsions; and PA1 (f) Corrosion and rust developed on workpieces, primarily due to used water.
It is thus desired to develop a water-soluble lubricant which can provide beautiful surfaces without leaving any stains, which have tended to occur by lube-oils, on the surfaces of workpieces after completion of their working, and does not permit inclusion of foreign or fouled matters such as metal powder and deteriorated lubricants, in other words, does not hold such foreign and/or fouled matters in the lubricant system and is therefore free from fouling workpieces. Under the present circumstances, there has not yet been found any excellent lubricant which exhibits such advantageous effects.